What might happen if the neutral feeder conductor is undersized?

The situation where a neutral feeder conductor is undersized can lead to overheating. This occurs because an undersized conductor cannot safely carry the amount of electrical current that flows through it, which results in resistance. As current flows through the conductor, this resistance causes it to generate heat. If the conductor is not rated for the amount of current it carries, it can reach high temperatures that may cause insulation to degrade or even lead to electrical fires. Therefore, ensuring that the neutral feeder conductor is adequately sized to handle expected loads is critical for safety and maintaining the integrity of the electrical system.

In contrast, underperformance, increased efficiency, or lower voltage typically do not directly result from an undersized neutral conductor. Underperformance could relate to other issues in the system, while increased efficiency and lower voltage are not characteristics one would expect from a conductor that cannot handle the electrical demands placed upon it.